In this study, we explored the design and optimization of misalignmenttolerant
broadband photonics edge coupler facets for use in a coupling scenario
between a DFB laser die and a Photonic Integrated Circuit (PIC).
To improve the efficiency of the optimization process, we implemented an
Artificial Neural Network (ANN) model that estimates the coupling performance
of an edge coupler facet and then optimizes it using Particle Swarm
Optimization. We examined three different edge coupler facet designs in
this study, with the first design having a maximum coupling efficiency of
around 0.866 and a 3-dB misalignment tolerance of 0.9 micrometers, the
second design having a maximum coupling efficiency of around 0.963 and
a 3-dB misalignment tolerance of 0.8 micrometers, and the third design
having a maximum coupling efficiency of around 0.604 and a 3-dB misalignment
tolerance of around 1 micrometer. Moreover, The transmission
in the C and L bands for the first design was found to be in the range of 0.853
to 0.884, while the second design was in the range of 0.957 to 0.97, and the
third design had a transmission between 0.557 to 0.703. Furthermore, we
also designed full-edge coupler designs and analyzed their performance
in FDTD. The FDTD simulation results in a consistent loss compared to
the FDE simulation and statistical prediction. For example, for the perfect
alignment setting, the additional transmission loss is around 1 dB. Although
the simulation result is not accurate, it is precise, and thus the result is still
valid.

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